Considering how little clear coat there is on B pillars and how soft it is you only need a finishing polish with a soft pad (black for starters, then white if need to) so I agree with Gonz only using DJ Micro prime.

Jon H who used Megs UC...yeah it looks good but he removed way too much clear coat needed. Do that 2-3 times and youll burn through.

There hasn't been any clearcoat on any of the B pillars I've ever worked on.

Considering how little clear coat there is on B pillars and how soft it is you only need a finishing polish with a soft pad (black for starters, then white if need to) so I agree with Gonz only using DJ Micro prime.

Jon H who used Megs UC...yeah it looks good but he removed way too much clear coat needed. Do that 2-3 times and youll burn through.

I didn't realise it was clear coat. What is it made of? I thought it was a high gloss plastic.

If the B pillars were clear coated the finish would be as hard as the paint on the body.

However, the finish is uncoated plastic which is soft by nature and hence why it marks easily.

Alan W

The B-pillars are definitely clear coated. The reason the clear isn't as 'hard' as the rest of the car is you can't exactly bake plastic at the same heat you'd bake the metal in.

I have detailed many, many many VW's (>50) and the only time you will get black transfer onto the pad is when the clear has been compromised, mostly on the edges of the pillars.

Typically if you look at the pillars you will see they do not sit flush with each other and are not at same angle, and so unless some careful taping has been done, the edges always get hammered and the clear compromised.

Menzerna SF4000 on a black pad should be all that is needed. I;ve often used PF2300 on a white pad for really bad ones.

I even did some wetsanding on a set on a Range Rover sport which had been taken off road and has some deep scratches from the bush

I've used Chemical Guys Blacklight as an all in one via either white or yellow Rupes pads, depending on how bad the damage is.
Edit - the pillars must have some sort of clear on top otherwise you'd get paint transfer every time you polished. If it was just the pure soft black plastic then any bits removed from polishing would therefore show as black on the pad each time.

Of course they have clear coat on gloss bi pillars, if the OP is picking up any black marks on his pad then he is catching the rubber edges of the pillars. When the car is painted the pillars are not attached, they are added on further on the production line, so that's why they are not as hard like the rest of the paint.